// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_RENDERER_PEPPER_V8_VAR_CONVERTER_H_
#define CONTENT_RENDERER_PEPPER_V8_VAR_CONVERTER_H_

#include <memory>

#include "base/callback.h"
#include "base/compiler_specific.h"
#include "base/macros.h"
#include "content/common/content_export.h"
#include "ppapi/c/pp_instance.h"
#include "ppapi/c/pp_var.h"
#include "ppapi/shared_impl/scoped_pp_var.h"
#include "v8/include/v8.h"

namespace content {

class ResourceConverter;

class CONTENT_EXPORT V8VarConverter {
public:
    // Whether or not to allow converting object vars. If they are not allowed
    // and they are passed in, conversion will fail.
    enum AllowObjectVars {
        kDisallowObjectVars,
        kAllowObjectVars
    };
    V8VarConverter(PP_Instance instance, AllowObjectVars object_vars_allowed);

    // Constructor for testing.
    V8VarConverter(PP_Instance instance,
        std::unique_ptr<ResourceConverter> resource_converter);
    ~V8VarConverter();

    // Converts the given PP_Var to a v8::Value. True is returned upon success.
    bool ToV8Value(const PP_Var& var,
        v8::Local<v8::Context> context,
        v8::Local<v8::Value>* result);

    struct VarResult {
    public:
        VarResult()
            : completed_synchronously(false)
            , success(false)
        {
        }

        // True if the conversion completed synchronously and the callback will not
        // be called.
        bool completed_synchronously;

        // True if the conversion was successful. Only valid if
        // |completed_synchronously| is true.
        bool success;

        // The result if the conversion was successful. Only valid if
        // |completed_synchronously| and |success| are true.
        ppapi::ScopedPPVar var;
    };

    // Converts the given v8::Value to a PP_Var. Every PP_Var in the reference
    // graph in the result will have a refcount equal to the number of references
    // to it in the graph. The root of the result will have one additional
    // reference. The callback is run when conversion is complete with the
    // resulting var and a bool indicating success or failure. Conversion may be
    // asynchronous because converting some resources may result in communication
    // across IPC. |context| is guaranteed to only be used synchronously. If
    // the conversion can occur synchronously, |callback| will not be run,
    // otherwise it will be run.
    VarResult FromV8Value(
        v8::Local<v8::Value> val,
        v8::Local<v8::Context> context,
        const base::Callback<void(const ppapi::ScopedPPVar&, bool)>& callback);
    bool FromV8ValueSync(v8::Local<v8::Value> val,
        v8::Local<v8::Context> context,
        ppapi::ScopedPPVar* result_var);

private:
    // Returns true on success, false on failure.
    bool FromV8ValueInternal(v8::Local<v8::Value> val,
        v8::Local<v8::Context> context,
        ppapi::ScopedPPVar* result_var);

    PP_Instance instance_;

    // Whether or not to support conversion to PP_VARTYPE_OBJECT.
    AllowObjectVars object_vars_allowed_;

    // The converter to use for converting V8 vars to resources.
    std::unique_ptr<ResourceConverter> resource_converter_;

    DISALLOW_COPY_AND_ASSIGN(V8VarConverter);
};

} // namespace content

#endif // CONTENT_RENDERER_PEPPER_V8_VAR_CONVERTER_H_
